1. Field of the Invention
The present invention is generally directed to measuring the relative angular orientation of two surfaces.
2. Discussion of Similar Art
The most common angular orientation measuring method involves using surveyor techniques to measure the position of a roll against a nearby offset reference line as disclosed by Loen, U.S. patent application Ser. No. 10/802,338 filed on Mar. 18, 2004. Other patents have been granted that use various lasers, sighting instruments, attaching fixtures, surveyor instruments, mirrors, targets, scales, and computers. These devices have unique features that allow an operator to measure angular orientation, especially parallel and perpendicular orientation, to various degrees of accuracy.
For example, U.S. Pat. No. 6,049,378 by Busch, et. al. describes an alignment measuring system where a gyroscope with positional sensors are used to determine the angular orientation of an object, such as a roll. The measuring apparatus is very expensive due to the electronics necessary to measure small angular orientation angles. U.S. Pat. No. 5,430,539 by Lysen, uses multiple laser beams, targets, and a computer to determine angular orientation. The methods described are complicated, stationary, and limited to a particular measurement of two fixed and adjacent rolls. U.S. Pat. No. 4,298,281 by Schave describes an offset system where a light beam is aligned to an offset reference line and the beam is reflected off the roll ends to measure angular orientation. For accuracy, this method depends heavily on aligning the light beam to an offset reference line. It also requires that the roll ends correctly reflect the angular orientation of the roll's working surface.
Other angular orientation measuring patents have significant limitations. Some are designed to measure the orientation of very specific surfaces. Others have practical restrictions where the methods disclosed are difficult to implement due to poor access to the surfaces needed for the orientation measurement. Many of the disclosed methods are based on nearby reference lines. The measuring equipment must first be adjusted or calibrated against those lines. This requires an additional time consuming step. Many of the techniques already patented require specialized training in order to ensure accurate measurements. Often, a separate and specially trained crew is required to make the measurements.
Further, many of the methods patented are relatively expensive due to the use of multiple precision components. Also, as a practical matter, it is easy to drop precision equipment and damage delicate instruments. Diode lasers, for example, are easily damaged or loose calibration when dropped. Some of the methods require heavy instruments that are difficult for an operator to lift and place upon the surface to be measured.
It is also important to provide for a high level of confidence in the angular measurement. Some orientation measuring methods require the use of lasers that are subject to thermal drift. This lowers confidence in any measurement that requires the laser beam projection angle to be consistent with calibration of the instrument. The device and method of this invention do not require any angular calibration system to check its accuracy.
3. Objects and Advantages
It is therefore desirable to provide a convenient, accurate, quick, reliable, affordable, and simple method of measuring surface to surface orientation without the need for specialized training. Consideration is given to creating a measuring instrument that is robust and easy to use. It is also designed to provide for accurate measurement which is free of the need for angular calibration of the measuring device.
It is further an object of this invention to measure the orientation of a wide variety of surfaces. The surfaces to be measured may be straight, curved, flat, convex, or concave. The surface may be defined by multiple objects. The mounting frames may include matching curves or surfaces to provide for accurate angular orientation measurements. An important objective of this invention is to measure the angular orientation of two rolls.